JP5773445B2 - Multilayer ceramic electronic component and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer ceramic electronic component and a method for manufacturing the same.

  In recent years, in accordance with the demand for downsizing and high functionality of electronic products, products such as IT and A / V, there has been a demand for downsizing and high functionality of electronic components. It is increasing. Multilayer ceramic electronic components are widely used as components for computers, mobile phones, and the like because of their advantages of being small in size and ensuring high capacity and being easy to mount.

  Multilayer ceramic electronic components include capacitors, inductors, varistors, and the like. In general, multilayer ceramic capacitors, which are the most widely used passive elements, are required to be small, high capacity, and highly reliable.

  To reduce the size and increase the capacity of multilayer ceramic capacitors, it is necessary to reduce the thickness and thickness of the ceramic sheet and internal electrodes. The volume ratio of the internal electrodes of the multilayer ceramic capacitors increases as the thickness and thickness of the multilayer ceramic capacitors increase. The cover layer thickness is reduced.

  As the thickness of the cover layer decreases, moisture and the like may permeate from the outside, and the moisture resistance characteristics of the multilayer ceramic capacitor may be degraded.

  An object of this invention is to provide the multilayer ceramic electronic component excellent in the moisture-proof characteristic, and its manufacturing method.

A multilayer ceramic electronic component according to an embodiment of the present invention includes a ceramic main body, an external electrode formed on an external surface of the ceramic main body, and an internal electrode arranged in a stack with a ceramic layer sandwiched in the ceramic main body. The ceramic body includes an active region from the uppermost internal electrode to the lowermost internal electrode and a cover region in contact with the upper and lower sides of the active region, and an average diameter D _c of the ceramic grains in the cover region is within the active region. smaller than the average diameter _{D a} of the ceramic grains, the thickness of the cover region when the _{T c,} a 9μm ≦ _{T c} ≦ _25μm, can be a T _c / _D c ≧ 55.

The average diameter D _c of the ceramic grain in the coverage area may be an average diameter in the thickness direction.

1.1 ≦ D _a / D _c ≦ 4.4.

  The ceramic body may include a dielectric material, and the dielectric material may include barium titanate or strontium titanate.

  The number of stacked internal electrodes may be 250 or more.

  The internal electrode may include one or more selected from the group consisting of nickel, palladium, and alloys thereof.

  The external electrode may include one or more selected from the group consisting of nickel, a nickel alloy, and palladium.

A multilayer ceramic electronic component according to another aspect of the present embodiment includes a ceramic main body including an internal electrode stacked portion in which a plurality of internal electrodes are stacked, and an external electrode formed outside the ceramic main body. In the main body, the thickness T _c of each of the upper and lower cover regions outside the internal electrode laminate is 9 to 25 μm, and the average diameter D _c of the ceramic grains in the external region of the internal electrode laminate is the internal electrode smaller than the average diameter _{D a} of the ceramic grains of the inner area of the laminate _may be a T _c / _D c ≧ 55.

  In the internal electrode stacked portion, adjacent internal electrodes can be drawn out in opposite directions.

  The external region may be disposed in the stacking direction of the internal electrodes of the internal electrode stack portion.

The average diameter D _c of the ceramic grains of the external region can be a mean diameter in the thickness direction.

1.1 ≦ D _a / D _c ≦ 4.4.

  The ceramic body may include a dielectric material, and the dielectric material may include barium titanate or strontium titanate.

  The number of stacked internal electrodes may be 250 or more.

  The internal electrode may include one or more selected from the group consisting of nickel, palladium, and alloys thereof.

  The external electrode may include one or more selected from the group consisting of nickel, a nickel alloy, and palladium.

  A method of manufacturing a multilayer ceramic electronic component according to another embodiment of the present invention includes a first ceramic powder and a second ceramic having an average particle size 1.1 to 4.4 times the average particle size of the first ceramic powder. Producing a powder; producing first and second ceramic green sheets using the first and second ceramic powders; and forming an internal electrode on the second ceramic green sheet. And laminating the first ceramic green sheets to form an upper cover and a lower cover having a thickness of 11 to 28 μm, and laminating the second ceramic green sheets having the internal electrodes in a desired number of layers. Forming a second ceramic green laminate, and laminating the lower cover, the second ceramic green laminate, and the upper cover. And a stage that can include.

  In the step of manufacturing the first and second ceramic powders, the first and second ceramic powders may include barium titanate powder.

  In the step of forming the internal electrode, the internal electrode may be formed by printing a conductive paste.

  The conductive paste may include a conductive metal, and the conductive metal may include one or more selected from the group consisting of nickel, palladium, and alloys thereof.

  According to the present invention, a multilayer ceramic electronic component having excellent moisture resistance and a method for producing the same can be obtained.

1 is a perspective view of a multilayer ceramic electronic component according to an embodiment of the present invention. It is sectional drawing which follows the XX 'line | wire of FIG. It is an enlarged view of the Y part of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  Embodiments of the present invention can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

  Also, the embodiments of the present invention are provided to more fully explain the present invention to those having average knowledge in the art.

  The shape and size of elements in the drawings may be exaggerated for a clearer description, and elements indicated by the same reference numerals in the drawings are the same elements.

  1 is a perspective view of a multilayer ceramic electronic component according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line XX ′ of FIG. 1, and FIG. 3 is an enlarged view of a Y portion of FIG. is there.

  Referring to FIG. 1, a multilayer ceramic electronic component according to an embodiment of the present invention includes a ceramic body 10, external electrodes 21 and 22 formed outside the ceramic body, and internal electrodes stacked inside the ceramic body. 31 and 32 can be included.

  The ceramic body 10 is a rectangular parallelepiped, and the L direction can be defined as the “length direction”, the W direction as the “width direction”, and the T direction as the “thickness direction”. The stacking direction of the internal electrodes 31 and 32 is the thickness direction. The ceramic body 10 can have both cross-sections S1 and S4 in the length direction, both side surfaces S2 and S5 in the width direction, and upper and lower surfaces S3 and S6 in the thickness direction.

  The ceramic body 10 is made of ceramic, and the ceramic is a dielectric material having a high dielectric constant. Specifically, the ceramic body 10 can contain barium titanate and strontium titanate.

  The external electrodes 21 and 22 can be formed to face the exteriors S1 and S4 of the ceramic body. The external electrode can be formed to extend on a part of the other surfaces S2, S3, S5, and S6 adjacent to each other, and the adhesion force of the external electrode to the ceramic body can be improved.

  A plating layer may be formed on the external electrode for ease of mounting. The external electrodes 21 and 22 are made of a conductive metal, and are not limited thereto, and can be made of copper, copper alloy, nickel, nickel alloy, silver, palladium, etc., in order to prevent penetration of the plating solution, etc. Glass can be included.

  The external electrodes 21 and 22 can be formed on both side surfaces S1 and S4 in the length direction of the ceramic body. At this time, the external electrodes 21 and 22 may be formed so as to be electrically connected to the internal electrodes 31 and 32 formed to be exposed on one surface of the ceramic body 10.

  The internal electrodes 31 and 32 can be formed by laminating the ceramic body 11 with the ceramic layer 11 interposed therebetween. The internal electrodes 31 and 32 include a conductive metal such as nickel and can be fired at a low temperature. The conductive metal can include one or more selected from the group consisting of gold, silver, copper, nickel, platinum, palladium, and alloys thereof.

  Further, a ceramic co-material having a high sintering temperature such as barium titanate can be added to the internal electrode to increase the sintering start temperature. This is to suppress the case where the sintering temperature of the internal electrode is lower than that of the ceramic, the internal electrode is sintered before the ceramic, and the coverage of the internal electrode is reduced, making it difficult to realize the capacitance.

  The number of internal electrodes stacked may be 250 or more. This is because the number of stacked internal electrodes is increasing with the trend of increasing the capacity of electronic components, and if the number of stacked internal electrodes is less than 250, it may be difficult to realize a high capacity. Note that the thickness of the internal electrode is also reduced for higher capacity.

  Referring to FIG. 2, the ceramic body 10 may be divided into an active area A and a cover area C in the thickness direction. The cover region C can be formed in contact with the upper and lower sides of the active region A. That is, the cover region C can be formed in contact with the active region A on the outer side of the ceramic body 10 with respect to the active region A in the stacking direction of the internal electrodes.

  The active area A is an area where internal electrodes are stacked, and can mean an area from the uppermost internal electrode 31a to the lowermost internal electrode 32a. The active region can contribute to the realization of the capacitance. The uppermost internal electrode 31a is an internal electrode arranged at one end in the stacking direction of the internal electrodes of the internal electrode group composed of a plurality of stacked internal electrodes, and the lowermost internal electrode 32a is the internal electrode It is an internal electrode arranged at the other end of the group in the stacking direction.

  The cover region C can mean a region from the uppermost internal electrode 31a to the upper surface S3 of the ceramic body. The cover area does not contribute to the realization of the capacity.

The cover area C can be formed above and below the active area A, which are referred to as an upper cover area and a lower cover area, respectively. The upper and lower regions can be symmetric. As the capacity increases, the thickness _Tc of the cover region tends to decrease.

In this embodiment, the thickness _Tc of the cover region can be 9-25 μm after firing.

As the capacity increases, the thickness _Tc of the cover region may gradually decrease. In the present invention, when the thickness _Tc of the cover region is 25 μm or less, the grain size of the cover region C and the active region A is adjusted to prevent deterioration of the moisture resistance and to ensure reliability.

However, since the thickness T _c of the thickness T _c is 9μm smaller when the cover region of the cover region is too thin, moisture resistance regardless grain size of the coverage area C and the active region A may be reduced .

In the present embodiment, the average diameter D _c of the ceramic grains in the cover region C can be smaller than the average diameter D _a of the ceramic grains in the active region A.

Why the grain diameter D _c of the cover region is smaller than the diameter D _a of the active region of the grain it is as follows.

  The ceramic powder sinters at lower temperatures as the surface area increases. This is because the larger the surface area of the ceramic powder, the higher the surface energy, and the overall state is energetically unstable. By lowering the surface energy, the ceramic powder moves in a more stable state. This is because this point acts as a driving force for sintering.

  When the ceramic powder in the active region A and the ceramic powder in the cover region C have the same size, sintering is performed in the order of the internal electrodes 31 and 32 in the active region A, the ceramic layer 11 and the margin 12 in the active region A, and the cover region C. Can happen. The order of the above-mentioned sintering is not absolute but conceptually divided, and in fact, sintering can occur simultaneously.

  The reason why the internal electrode is sintered first is that the sintering temperature of the conductive metal used for the internal electrode is lower than that of the ceramic powder.

  Next, the ceramic layer 11 and the margin part in the active region are sintered. This is because compressive stress acts on the ceramic layer between the internal electrodes due to contraction of the internal electrodes during the sintering process of the internal electrodes, and this acts as a driving force for sintering.

  Finally, the cover area C is sintered.

  Since the sintering temperature varies depending on the position as described above, the stress is unevenly distributed inside the ceramic body, which may directly induce defects such as delamination and cracks.

  In addition, it may act as a potential risk factor for generating a defect due to external impact (thermal shock) or the like through subsequent steps. In the case of an ultra-high-capacity product, the ratio of the thickness of the cover region to the volume ratio of the internal electrode is reduced, so the above problem may be further deepened.

  By reducing the size of the ceramic powder particles in the cover region C and lowering the sintering temperature of the cover region, the difference in the sintering temperature of the active region can be reduced, thereby reducing the unevenness in the ceramic body. The stress distribution can be relaxed.

  Eventually, by making the grain size of the cover area smaller than the grain size of the active area, it is possible to suppress the occurrence of delamination and cracks, and a potential risk factor that causes defects even after subsequent thermal shock Moisture resistance can be improved by relaxing.

Specifically, the ratio (D _a / D _c ) of the grain diameter D _a of the active area to the diameter D _c of the grain of the cover area may be 1.1 to 4.4.

When D _a / D _c is smaller than 1.1, the size of the ceramic powder particles used in the active region and the cover region are similar, and thus there is a non-uniformity of stress distribution between the active region and the cover region. Delamination and cracks may occur, and the effect of improving moisture resistance is low.

If D _a / D _c is greater than 4.4, the size of the ceramic powder particles used in the active region is too large than the size of the ceramic powder particles used in the cover region. There is a possibility that the stress imbalance will deepen. This is because the cover area is sintered faster than the active area.

The average diameters D _c and D _a of the ceramic grains can be measured by analyzing a cross-sectional photograph of the cover region C or the active region A extracted by a scanning electron microscope (SEM). For example, the average diameters D _c and D _a of the ceramic grains can be measured using grain size measurement software that supports the average size standard measurement method defined by ASTM (American Society for Testing and Materials) E112.

  An area containing 30 or more grains in the cover area and the active area is sampled, and the average diameter of the grains can be measured using the above method. Specifically, the length and thickness direction cross section (L-T cross section) at the center when the width direction (W direction) of the ceramic body 10 is equally divided into three by a scanning electron microscope (SEM, Scanning Electron Microscope). The sampling can be performed from the scanned image.

The ratio of the thickness T _c of the cover region to the average diameter D _c in the thickness direction of the grains of the cover region can be 55 or more (T _c / D _c ≧ 55). That is, the number of grains arranged in the thickness direction in the cover region can be 55 or more.

The average diameter D _c in the thickness direction of the grain of the cover region can be defined as a value obtained by dividing the value of the combined measuring the thickness direction of the diameter of the grain in the coverage area by the number of grains. Specifically, the length and thickness direction cross section (L-T cross section) at the center when the width direction (W direction) of the ceramic body 10 is equally divided into three by a scanning electron microscope (SEM, Scanning Electron Microscope). In the scanned image, it can be measured at each point where the central portion when the length direction is equally divided into three is equally divided into ten.

The thickness T _c of the cover region can be an average value. Specifically, the length and thickness direction cross section (L-T cross section) at the center when the width direction (W direction) of the ceramic body 10 is equally divided into three by a scanning electron microscope (SEM, Scanning Electron Microscope). In the scanned image, the average value of the thickness of the cover region measured at each point obtained by equally dividing the central portion into three equal parts in the length direction may be defined as the thickness T _c of the cover region. it can.

Can be defined as the number of the thickness direction of the grain of the cover region thickness T _c was divided in the thickness direction of the diameter D _c of the grain value (T c _{/ D c)} of the cover region.

  The greater the number of grains in the thickness direction in the cover region, the better the moisture resistance. Moisture permeation from the outside to the inside of the ceramic body is performed through grain boundaries rather than inside the grains. This is because the greater the number of grains, the longer the permeation path.

The multilayer ceramic electronic component according to another aspect of the present embodiment includes a ceramic main body 10 including an internal electrode laminated portion A in which a plurality of internal electrodes are laminated, and external electrodes 21 and 22 formed outside the ceramic main body 10. In the ceramic body 10, the thickness T _c of the external region C of the internal electrode laminate A is 9 to 25 μm, and the average diameter D _c of the ceramic grains in the external region C of the internal electrode laminate A is smaller than the average diameter D _a of the ceramic grains in the internal region of the internal electrode laminate unit a, it can be a T _{c /} D c ≧ 55.

  The ceramic body 10 can be divided into an internal electrode laminated portion A and an external region C formed above and below in the thickness direction of the ceramic body 10. The internal electrode laminate portion A may mean a region where the internal electrodes 31 and 32 are laminated in the ceramic body 10. Adjacent internal electrodes 31 and 32 in the internal electrode laminated portion A are drawn out in directions opposite to each other, and electricity having opposite polarities can be applied.

  External regions C can be formed above and below the internal electrode laminate A. That is, the external region C can be disposed on the outer side of the ceramic body 10 in the stacking direction of the internal electrodes of the internal electrode stacking portion A.

The average diameter D _c of the ceramic grains of the external region can be a mean diameter in the stacking direction.

1.1 ≦ D _a / D _c ≦ 4.4.

  The ceramic body can include a dielectric material.

  The dielectric material can include barium titanate or strontium titanate.

  The number of stacked internal electrodes may be 250 or more.

  The internal electrode may include one or more selected from the group consisting of nickel, palladium, and alloys thereof.

  The external electrode may include one or more selected from the group consisting of nickel, a nickel alloy, and palladium.

  Other matters relating to the ceramic body, internal electrodes, external electrodes, etc. are the same as described above.

  A method of manufacturing a multilayer ceramic electronic component according to another embodiment of the present invention includes a first ceramic powder and a second ceramic having an average particle size 1.1 to 4.4 times the average particle size of the first ceramic powder. Producing a powder; producing first and second ceramic green sheets using the first and second ceramic powders; and forming an internal electrode on the second ceramic green sheet. And laminating the first ceramic green sheets to form an upper cover and a lower cover having a thickness of 11 to 28 μm, and laminating the second ceramic green sheets having the internal electrodes in a desired number of layers. Forming a second ceramic green laminate, and laminating the lower cover, the second ceramic green laminate, and the upper cover. And a stage that can include.

  The first ceramic powder particles can be smaller in size than the second ceramic powder particles. Specifically, the average particle size of the second ceramic powder particles is preferably 1.1 to 4.4 times the average particle size of the first ceramic powder particles.

  The ratio of the grain diameter in the active area to the grain diameter in the cover area after sintering can also be adjusted to a range of 1.1 to 4.4. The diameters of the sintered first and second ceramic grains may be larger than the first and second ceramic powder particles before sintering, respectively, but the first and second ceramic powder particles are sintered together. As a result, the ratio does not change significantly.

  The first ceramic powder can be used to produce a ceramic sheet for the cover area, and the second ceramic powder can be used to produce a ceramic sheet for the active area.

  After mixing an organic solvent, a binder, etc. with the 1st ceramic powder, this is ball-milled and a ceramic slurry is manufactured, A 1st ceramic green sheet can be manufactured using methods, such as a doctor blade.

  A second ceramic green sheet can be produced from the second ceramic powder using the same method as described above.

  The first and second ceramic powders can include barium titanate powder. Barium titanate has a high dielectric constant and can be induced to store electric charge to realize a high-capacitance capacitor.

  An internal electrode can be formed by printing a conductive paste on the second ceramic green sheet. On the other hand, the internal electrode need not be formed on the first ceramic green sheet.

  The conductive paste includes a conductive metal, and specifically, the conductive metal may include one or more selected from the group consisting of nickel, palladium, and alloys thereof.

  Gold, silver, platinum, palladium, and the like are expensive, but are stable and can be sintered in the atmosphere. On the other hand, nickel, copper, and the like are low in cost, but may be oxidized at the time of sintering, and may require sintering in a reducing atmosphere.

  The conductive metal is not limited to the above example as long as it can provide conductivity to the internal electrode.

  An upper cover and a lower cover can be formed by laminating the first ceramic green sheets. Considering the sintering shrinkage, the thickness of the upper cover and the lower cover is preferably 11 to 28 μm. Thereby, the thickness of the cover region can be 9-25 μm after sintering.

  A second ceramic green laminate can be formed by laminating the second ceramic green sheets on which the internal electrodes are formed. By setting the number of stacked internal electrodes to 250 or more, a high capacity can be realized. The second ceramic green laminate can subsequently form an active region.

  The bottom cover, the second ceramic green laminate, and the top cover can be laminated to form the final green laminate.

  By cutting, calcining, and sintering the green laminate, a sintered chip is manufactured, an external electrode is formed by a dipping method with a conductive paste outside the sintered chip, and this is baked, Multilayer ceramic electronic components can be manufactured.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

  The multilayer ceramic capacitor according to the example was manufactured as follows.

  First, in order to diversify the grain size in the active region, an appropriate barium titanate powder was selected and used within an average particle size range of 0.05 to 3 μm.

  The barium titanate powder was mixed with ethanol as an organic solvent and polyvinyl butyral as a binder, and then ball-milled to produce a ceramic slurry, which was used to produce a ceramic green sheet for an active region.

  Further, in order to diversify the grain sizes in the cover region, a suitable ceramic green sheet for the cover region was manufactured by selecting an appropriate barium titanate powder within an average particle size range of 0.05 to 3 μm.

  Next, internal electrodes were printed on the active region ceramic sheet using a conductive paste containing nickel metal.

Next, 3-8 sheets of ceramic sheets for the upper cover area, 250 sheets of ceramic sheets for the active area, and 3-8 sheets of ceramic sheets for the lower cover area were sequentially laminated at 1000 ° C. at 85 ° C. Isostatic pressing at a pressure of cm ² was performed.

The bonded ceramic laminate was cut into individual chips, and the cut chips were maintained in an air atmosphere at 230 ° C. for 60 hours for binder removal. Thereafter, firing was performed at 950 to 1200 ° C. under an oxygen partial pressure of 10 ⁻¹¹ to 10 ⁻¹⁰ atm lower than the Ni / NiO equilibrium oxygen partial pressure so that the internal electrode was not oxidized.

  After polishing the outer surface of the fired chip, the fired chip was dipped in an external electrode conductive paste and baked to form an external electrode. The conductive paste for external electrodes was produced by adding glass, binder, etc. to copper powder. A tin plating layer was formed on the surface of the external electrode by electroplating.

The multilayer ceramic electronic component of the comparative example is manufactured by the same method as in the embodiment, except that the thickness T _{c of} the cover region and the average particle size of the barium titanate powder used in the cover region and the active region are different. It was.

  The ceramic capacitor manufactured by the above method was subjected to a moisture resistance load test, and the insulation resistance (IR) was measured before and after the moisture resistance load test to evaluate the reliability.

  In the moisture resistance load test, a rated voltage of 1.5 Vr was applied for 500 (+ 12 / −0) hr in a temperature of 40 ± 2 ° C. and a humidity of 90 to 95% RH, and the charge / discharge current was 50 mA or less.

  Insulation resistance (IR) was measured after heat treatment at 150 ° C. (+ 0 / −10) ° C. for 1 hour and standing at room temperature for 24 (± 2) hours before and after the moisture resistance load test.

  Considering product standards, those having an insulation resistance of 50 MΩ or more before the moisture resistance load test and having an insulation resistance of 3.5 MΩ or more after the moisture resistance load test were determined to be good.

After molding the sample subjected to the moisture resistance load test, an SEM photograph was taken on the polished cross section, and based on this, the thickness T _{c of} the cover region, and the diameter D _c of the ceramic grains in the cover region and the active region were taken. , _Da was measured.

Tables 1 to 5 show cases where the thickness _Tc of the cover region is 6 μm, 9 μm, 15 μm, 25 μm, and 35 μm, respectively.

Table 1 shows the reliability evaluation results for the multilayer ceramic capacitor having a cover region thickness _Tc of 6 μm.

Referring to Table 1, all of Comparative Examples 1 to 3 indicate that the insulation resistance value does not reach the standard value regardless of the values of T _c / D _c and D _a / D _c , indicating that they are defective. . This is because the cover region is too thin.

Table 2 shows the reliability evaluation results for the multilayer ceramic capacitor having a cover region thickness _Tc of 9 μm.

Referring to Table 2, Examples 1 to 3 are cases where T _c is 9 μm, T _c / D _c is 100, and D _a / D _c is 1.1, 2.0, and 4.4. Shows good results. In conclusion, the moisture resistance is good when D _a / D _c is 1.1 to 4.4.

  In the case of Examples 4-6, the result similar to Examples 1-3 is shown.

Comparative Example 4 is a case where T _c is 9 μm, T _c / D _c is 100, and D _a / D _c is 1.0, indicating a poor reliability. This is because the size D _a of the grains of grain size D _c and the active region of the cover region are similar, less effective to alleviate the uneven stress distribution due to the difference in sintering temperature of the cover region and the active region Because.

Comparative Example 6 is a case where T _c is 9 μm, T _c / D _c is 164, and D _a / D _c is 1.0, which is the same as the case of Comparative Example 4.

Comparative Example 5 is a case where T _c is 9 μm, T _c / D _c is 100, and D _a / D _c is 4.6, indicating a poor reliability. This is because the size of the grain in the cover area is too small than the grain size in the active area, so that the cover area is sintered faster and this causes the internal stress distribution to be non-uniform.

Comparative Example 7 is a case where T _c is 9 μm, T _c / D _c is 164, and D _a / D _c is 4.6, which is the same as the case of Comparative Example 5.

Comparative Examples 8 to 12 are cases where T _c is 9 μm, T _c / D _c is 50, and D _a / D _c is 0.9 to 4.6, and all show poor reliability. This is because T _c / D _c is as small as 50 regardless of the D _a / D _c value. That is, T _c / D _c means the average number of grains in the thickness direction existing in the cover region, because the number of grains is less than 55 and the moisture permeation path is shortened.

Tables 3 and 4 show the reliability evaluation results for multilayer ceramic capacitors having cover region thicknesses _Tc of 15 μm and 25 μm, respectively. According to Tables 3 and 4, it can be confirmed that the results are similar to those in Table 2.

Table 5 shows the reliability evaluation results for the multilayer ceramic capacitor having a cover region thickness _Tc of 35 μm.

Referring to Table 5, Comparative Examples 31 to 40 _are, T _c / D _c, both regardless of the value of D a / _{D c} humidity resistance results are indicated better. This is because the thickness _Tc of the cover region is sufficiently thick.

  The following conclusions can be obtained from the above experimental results.

  First, when the thickness of the cover region is greater than 25 μm, the moisture resistance is excellent.

  Second, when the thickness of the cover region is 25 μm or less, there is a possibility that the moisture resistance characteristic may be deteriorated due to non-uniform stress distribution due to a difference in sintering temperature between the cover region and the active region.

However, the grain size of the cover area is made smaller than the grain size of the active area (1.1 ≦ D _a / D _c ≦ 4.4), and the number of grains in the thickness direction of the cover area is adjusted (T _c / By making D _c ≧ 55, the moisture resistance can be improved.

Third, when the thickness of the cover region is less than 9 μm, the moisture resistance cannot be improved even if the values of D _a / D _c and T _c / D _c are adjusted.

  The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. The singular form includes the plural meanings unless the context clearly indicates otherwise.

  Terms such as “including” or “having” are meant to exclude the presence of features, numbers, steps, operations, components or combinations thereof described in the specification. It is not something to do.

  The present invention is not limited by the above-described embodiments and the accompanying drawings, but is limited by the appended claims.

  Therefore, various forms of substitution, modification, and alteration can be made by those having ordinary knowledge in the art without departing from the technical idea of the present invention described in the claims. It belongs to the scope of the present invention.

10 ceramic body 11 ceramic layers 21 and 22 the mean diameter of the external electrodes 31 and 32 internal electrodes 31a uppermost internal electrode 32a grain lowermost internal electrode T _c average thickness D _c coverage area of the grain diameter D _a active region of the cover region

Claims (11)

A ceramic body;
An external electrode formed on the external surface of the ceramic body;
An internal electrode laminated in a ceramic body with a ceramic layer in between, and
Wherein the ceramic body includes an active region from the uppermost internal electrode to the lowermost internal electrode, formed in said top or bottom of the active region, and a cover area in contact with the uppermost inner electrode and the lowermost internal electrode,
The average diameter D _c of the ceramic grains in the cover region is smaller than the average diameter D _a of the ceramic grains in the active region, and 1.1 ≦ D _a / D _c ≦ 4.4,
A multilayer ceramic electronic component in which 9 μm ≦ T _c ≦ 25 μm and T _c / D _c ≧ 55, where T _c is a thickness of the cover region in the stacking direction of the internal electrodes. 2. The multilayer ceramic electronic component according to claim 1, wherein an average diameter D _c of the ceramic grains in the cover region is an average diameter in the stacking direction. A ceramic body including an internal electrode laminated portion in which a plurality of internal electrodes are laminated;
An external electrode formed outside the ceramic body,
In the ceramic body, a thickness T _c in the stacking direction of the internal electrodes in an external region in contact with the uppermost internal electrode or the lowermost internal electrode of the internal electrode stacked section on the outer side of the ceramic main body with respect to the internal electrode stacked section. Is 9 to 25 μm, and the average diameter D _c of the ceramic grains in the outer region is smaller than the average diameter D _a of the ceramic grains in the inner region of the internal electrode laminate, and 1.1 ≦ D _a / D _c ≦ 4. 4 and T _c / D _c ≧ 55.   4. The multilayer ceramic electronic component according to claim 3, wherein the internal electrode stacked portion is configured such that adjacent internal electrodes are drawn in opposite directions.   5. The multilayer ceramic electronic component according to claim 3, wherein the external region is disposed on an external side of the ceramic body in the stacking direction of the internal electrode stack portion. 6. The multilayer ceramic electronic component according to claim 3, wherein an average diameter D _c of the ceramic grains in the outer region is an average diameter in the stacking direction.   The multilayer ceramic electronic component according to claim 1, wherein the ceramic body includes a dielectric material.   The multilayer ceramic electronic component according to claim 7, wherein the dielectric material includes barium titanate or strontium titanate.   The multilayer ceramic electronic component according to claim 1, wherein the number of stacked internal electrodes is 250 or more.   10. The multilayer ceramic electronic component according to claim 1, wherein the internal electrode includes one or more selected from the group consisting of nickel, palladium, and alloys thereof.   11. The multilayer ceramic electronic component according to claim 1, wherein the external electrode includes one or more selected from the group consisting of nickel, a nickel alloy, and palladium.

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